I know loads of Facebook users who never bother to check their notifications. You know, that area in the top-left corner of the screen, the one with the little red number badges?

From left to right, those little icons consist of the following: Friend Requests, Inbox, and Notifications.

To me, all three are like inboxes, in that they should be checked and cleared out on a regular basis.

But let's talk about Inbox itself for a moment. When you click that icon, you'll see a list of messages (emails, for all intents and purposes) you've received from people you know.

However, what's very easy to overlook is the "Other" option, which is grayed out and barely visible atop the inbox frame. Click that; you may be surprised by the result.

Surprised, as in you have another inbox you didn't know you had. According to Facebook, the Other folder is "where you'll find messages and emails that have been filtered out of your inbox"--in other words, messages from people you probably don't know.

Now, you may have none at all. Or you may have a ton of them, all unread and unanswered. Hope there was nothing important in there from, like, two years ago.

This black hole goes hand in hand with Facebook's newly monetized messaging system, through which people can spend $1 to send you a message that lands in your proper inbox, and not the Other folder. And I suppose Facebook is banking on the fact that almost no one knows that folder exists.

So, consider this your public service announcement. And this as well: If you want to change your message-filtering preferences, Facebook offers a simple how-to. Except that step #3 is wrong: You won't see the Edit Preferences option unless you first click on one of the messages in your Other folder.

Any thoughts on this? Just par for the course with Facebook, that endlessly confusing beast, or much ado about nothing?

For more than 20 years, Rick Broida has written about all manner of technology, from Amigas to business servers to PalmPilots. His credits include dozens of books, blogs, and magazines. He sleeps with an iPad under his pillow.